this is what i use. I haven't had a problem with any roms. It tells you when a rom is already trimmed and never destroys the wifi in a game. I always overwrite the original rom, if you trim and have it move trimmed rom to another folder it takes longer. I've trimmed lists of 100 roms and this thing seems to trim those in like 30 seconds as long as you overwrite, if you place in another file after trimmed it obviously takes longer being it has to trim then move and write new rom to another folder. Good luck!!! I love this thing.